Wrong insulation

[Bald eagle]

My son in law has had a large 2 storey extension built on the side of the house. The builder put up the shell and he finished off, including fixing and finishing the plasterboard. Apparently during the build the Building Inspector on one of his visits noted that the wrong insulation had been used in the cavity walls. Not disastrous as he would accept it providing a specific type of plasterboard was used inside. This information was never passed on. On his final visit today he brought this point up and wants a hole cut in the plasterboard so that he can come back and confirm what has been used.

Assuming it's the wrong one will the problem be confined to outside walls, i.e. will internal walls be ok with standard plasterboard, and would fixing the correct plasterboard over the existing stuff be acceptable? Have only spoken briefly to my daughter so this is all the info I have at present - don't know specifics of what insulation was used and what type of plasterboard he required.

Any opinions welcomed!

JC

[leenowell]

Without knowing what plasterboard he said, it is difficult to comment. My suspicion is that the insulation he installed wasn't sufficient to meet the required heat loss regulations and that the plasterboard mentioned is insulated plasterboard - effectively plasterboard with polystyrene stuck on it. If this is the case, then it would only cover external walls. As for fixing, assuming the original plasterboard is screwed to a stud frame (?) I can't see why you can't screw this on top of it. If it is dabbed on, I believe you would be able to dab the new one on top but not sure this would be the best idea.

[TMC]

If that is the case why not just ask him what plasterboard he used?

If the correct type cut the hole in a inconspicuous place and refinish after BC has been

If the wrong type BC will say what will be necessary to rectify

I have had little luck second guessing Building Inspectors

Tony

Tony

[Bald eagle]

We know what plasterboard was used - bog standard wallboard. Have since heard that the builder admits forgetting to pass the message on and will liaise with the Inspector to agree how to rectify. I think leenowell was right in his reply - the cavity insulation was insufficient and insulated plasterboard should have been used. If so it will be only external walls involved. Not as bad as they first thought but a pain when they thought they had finished

JC

[John Rumm]

The only other possibility I can think of is that the BCO might have wanted a PB with a vapour barrier on it - like foil backed PB.

[Hugo Nebula]

On Tue, 20 Jan 2009 12:49:32 -0000, a certain chimpanzee, "Bald eagle" randomly hit the keyboard and produced:

If there are sockets or light switches in the external walls, you can undo these to allow the plasterboard to be seen.

If it's not there or not enough, check how far out the insulation in the cavity was. Depending on how much over the heat loss is, you may be able to offset it by additional insulation elsewhere, such as in the loft of the extension or the existing house. If your daughter is considering replacing a boiler, a higher efficiency one may offset the additional heat loss.

[Hugo Nebula]

On Tue, 20 Jan 2009 16:47:27 +0000, a certain chimpanzee, John Rumm randomly hit the keyboard and produced:

Not unless the inner leaf was timber. Even then, there should be a seperate vapour barrier. No, I'm almost certain from the information here is that it's an insulated plasterboard that's needed.